Sources of toxic particles in cities:
First: it's automobile exhaust. Large vehicles that use diesel are "recidivists" who emit PM 10, including buses, shuttle buses of various units and large transport trucks. Sources of toxic particulate matter in cities: firstly, automobile exhaust. Cars that use diesel are "habitual criminals" who emit particles. Small cars that use gasoline emit gaseous pollutants, such as nitrogen oxides, which are easily converted into secondary particulate pollutants in foggy days, aggravating smog.
Vehicle exhaust is the main component of smog particles. According to the latest data, motor vehicle exhaust accounts for 22.2% of smog particles in Beijing, and coal combustion accounts for 22.2%.
16.7%, dust 16.3%, industry 15.7%. However, with the progress of automobile technology and the improvement of oil quality, environmental protection managers have found that motor vehicle exhaust does not play a decisive role in the formation of haze weather, but
As some cities with a large number of cars, managers still need to control vehicle emission standards to avoid the formation of haze weather.
Second: the waste gas produced by burning coal for heating in winter in the north.
Third: the waste gas emitted by industrial production. For example, metallurgy, kilns and boilers, electromechanical manufacturing, automobile repair and paint and building materials production produce a lot of waste gas from kiln combustion.
Fourth: Dust generated by construction sites and road traffic. Puweixin Tiantong imported from the United States can effectively prevent smog.
Fifth, the particle size of growable particles, bacteria and viruses is equivalent to PM0.1-PM2.5. When the humidity and temperature in the air are appropriate, microorganisms will attach to particles, especially oil fume particles, which will adsorb oil droplets and transform them into more microorganisms, which will increase the growth of biotoxic substances in smog.
6. Dust "smog" will also be produced in home decoration. Indoor dust is pervasive, which is not only harmful to the health of staff and users, but also increases the cleaning burden. When the dust is serious, it also brings many hidden dangers to the decoration project. [4] [5]
In addition to meteorological conditions, there are industrial production, automobile exhaust emissions, heating and burning coal in winter. Causing particulate matter (including coarse particulate matter PM 10 and fine particulate matter)
The increase of PM2.5) concentration is an important factor of smog. At present, the level of pollutant discharge in many cities is at a critical point, which is very sensitive to meteorological conditions. Under good diffusion conditions, the air quality can reach the standard.
In case of adverse weather conditions, air quality and visibility will immediately decline.